Mask for light sources



July 24, 1956 F. zwlcK 2,756,325

MASK FOR LIGHT SOURCES Filed Nov. so, 195o Figa ///lf Figa i a Fgg United States Patent O 2,756,325 MASK Fon LIGHT SOURCES Franz Zwick, Ulm (Danube), Germany Application November 30, 1950, Serial No. 198,290

Claims priority, application Germany December 5, 1949 3 Claims.- ((1240-78) This invention concerns masks for light sources.

Various kinds of such masks are known, varying according to the purpose for which theyV are to be used. A primary consideration in such masks-is always the avoidance of dazzle from the light source, together with good light distribution, small light losses and pleasing appearance. These requisites may not, however, all be fully realised at the same time with known masks, because usually one advantage is attainable only at the cost of one of the otlie'rs.-

lt is an object of the invention to provide a mask for light sources in which these properties are all obtained in large degree, and which may be simply produced.

According to the present invention, a mask for light sources is composed of individual constructional parts which are injected or pressed from a transparent or translucent thermo-plastic mass of synthetic material and are formed in such a way that after the assembly of these a kind of grating is produced.

The constructional parts have projecting arms suitable for this purpose. They are preferably formed so as to be capable of plugging one into another and for this purpose are provided with claws and pegs.

The invention will be further described by way of example with reference to the accompanying drawings in which:

Figs. l to 3 show various constructional parts in side elevation,

Figs. 4 to 6 are the corresponding plan views,

Fig. 7 is a plan showing the constructional parts assembled together into a grating.

Fig. 8 shows the complete grating in side elevation on a smaller scale, constituting the facing of a light source.

Fig. 9 shows this facing as viewed from below.

The constructional parts 1, 2 and 3 have arms 4 lying at right angles to one another and projecting from the centres of the parts. The two constructional parts 1 and 3 each have three arms or walls and the constructional part 2 has four arms or walls. The ends of the two arms lying opposite to one another of the constructional part 1 are provided with cylindrical pegs 5 and the end of the further arm of this constructional part is provided with a claw 6. In the constructional part 2 two oppositely disposed arms carry pegs and the two other oppositely disposed arms carry claws 6. The constructional part 3 has claws 6 at the ends of the two oppositely disposed arms and a peg 5 on the other arm.

The grating 7 (Fig. 7) is composed of these constructional parts. The two longitudinal margins of the grating consist of the constructional parts 1 and 3 which follow one another alternately. The inner constructional elements of the grating are formed of the constructional parts 2 which are arranged side by side so that both in the longitudinal and in the transverse directions, adjacent parts are turned through 90 with respect to each other. It is thus achieved that a claw of one constructional part always encloses a peg of the adjacent constructional part. With the composition of the parts these are plugged one 2,756,325 Patented July 24, 1956 2 into another from above at their ends so that the' pegs are caused to engage inthe claws.

The grating 7 which` Fig. 9 shows completely on a smaller scale, forms in the example of applicationillustrated in Fig. 8 the maskv of a lighting tube 8 shown in side elevation, which' lighting Vtube 8 is fixed to the' ceiling ofthe rooin to be illuminated. The grating 7 is situated a small distance in front of this tube S andis carried by angled holding plates 10. i

The constructional parts ofV the Ymask. are injected or pressed from atransparent or translucent mass of thermoplastic synthetic material according .to the known processes using suitable moulds. In this way a rapid and convenient production is made4 possible, and true interlocking of each individual' constructional-part is obtained which is` of importance for the assembly of the manyv constructional parts of which the gratingconsists. The pegs 5 and claws 6 of each constructional part are moreover' sodimensioned that the claws embrace the pegs tightly on assembly of the parts whereby rmnes's is guaranteed. In case of necessity the constructional parts can be cemented together in the assembled position.

The small weight of the constructional parts (made in thermo-plastic material) is advantageous since it results in a mask which is light, convenient to manipulate and having a wide factor of safety. The relatively small heatstability of thermo-plastic bodies is moreover not disadvantageous even with only a small separation of the light source from the mask, since the grating form of the mask permits of good air circulation and hence of heat carrying away.

By refraction of light, the transparent `constructional parts of the grating give a good light distribution which can be further improved if the arms 4 of the constructional parts 1, 2 and 3 present light refracting unevennesses, particularly formed zig-zag or wave shaped or corrugated or are provided with special light refracting facets. In the illustrated embodiments the arms 4 have a zig-zag shaped coriugation. lf the constructional parts of the mask have a different kind of colouring one from another it is possible to attain by the appropriate composition any ornamental or mosaic-like constructional effects.

In the example of construction illustrated in the drawing the individual small constructional parts of the grating 7 are assembled together .in such a way that a at structure results. These can, however, be assembled in such a way as to be displaced relative to one another at their points of union 5 and 6 in an axial direction, whereby the structure is uneven. The grating is then completed with the upper and lower ends of the pegs S and claws 6 no longer ush with one another but lying at different heights. Hence any uneven three-dimensional structures may be produced, for example in the form of a more or less strong undulation of the grating 7.

The individually combining constructional parts can form prepared small partial gratings of the total grating 7. The partial grating is then produced in the appropriately formed injection or press mould in a single piece and it then has only the outwardly freely projecting arms for the pegs 5 and claws 6 necessary for the plugging of one into the other.

I claim:

l. For use in a grating for masking a light source, in combination, an element composed of two walls extending perpendicularly to each other and intersecting each other at the respective midpoints thereof; and male joining means located at and integral with two free ends of said side walls and female joining means located at and integral with another two free ends of said side walls for joining said element to additional elements of the same construction at the free ends of the walls thereof so that a male joining means of said element joins a female joining means of one of the additional elements and a female joining means of said element joins a male joining means of another of the additional elements, whereby a plurality of joined elements form a grating for masking a light source, said element and said joining means consisting of a material permeable to light. v

2. v For use in a grating for making a light source, in combination, an element composedy of two walls extending perpendcularly to each other and intersecting each other at the respective midpoints thereof, said walls being zig-zag shape so as to provide light refracting unevennesses; and male joining means located at and integral with two free ends of said side walls and female joining means located at located at and integral with the free ends of one of said and integral with another two free ends of said side walls 3. For use in a grating for masking a llight source, in

combination, an element composed of two walls extending perpendicularly to each other and intersecting each other at the respective midpoints thereof; and male joining means side walls and female joining means located at and integral with the free ends of the other of said side walls for joining said element to additional elements of the same construction at the free ends of the walls thereof so that a male joining means of said element joins a female joining means of one of the additional elements and a female joining means of said element joins a male joining means of another of the additional elements, whereby a plurality of joined elements form a grating formasking a light source, said element and said joining means consisting of a material permeable to light. l A 'Y References Cited in the le of this patent UMTEDv sTATEs- PATENTS 1,536,146 Sajert May 5, 1925 1,549,781 McCarley Aug. 18, 1925 2,022,078 Dorey Nov. 26, 1935 2,196,214 Kamal; Apr. 9, 1940 2,219,870 Jacobus Oct. 29, 1940 2,299,256 Schultz Oct. 20, 1942 2,406,759 Glukes Sept. 3, 1946 2,619,583 Baumgartner Nov. 25, 1952 FOREIGN PATENTS 176,493 Great Britain Mar. 7, 1922 498,805 Great Britain Ian. 13, 1939 

